Epidemiological evolution and molecular characterization of porcine enteric viruses in China from 2022–2025

Abstract Porcine enteric viruses are major etiological agents of viral diarrhea in piglets, posing a serious threat to the sustainable development of the swine industry. To systematically characterize the epidemiological status and evolutionary dynamics of porcine enteric viruses in China, we collected 736 diarrheic pig samples between 2022 and 2025 from Hubei, Jiangxi, Shanxi, Guizhou and Tibet Provinces. Molecular epidemiological surveillance and virus isolation were performed for porcine epidemic diarrhea virus (PEDV), group A porcine rotavirus (PoRVA), transmissible gastroenteritis virus (TGEV) and porcine deltacoronavirus (PDCoV). PEDV emerged as the predominant pathogen, with positivity rates increasing annually and reaching 70.75% in 2025. PoRVA ranked second, with a stable prevalence, whereas TGEV and PDCoV presented lower detection rates with regional variation. A total of six viral strains were successfully isolated, including two PEDV strains (HuB2023 and HuB2025), three PoRVA strains (HuB2023, JX2024 and SX2024) and one TGEV strain (JX2024). Phylogenetic analysis revealed that circulating PEDV evolved from G2a to G2c, with the detection of an S‑INDEL–like cluster. Notably, the PEDV HuB2025 represents a G2c recombinant strain harboring critical amino acid substitutions within the neutralizing epitopes of the spike protein. All PoRVA isolates belonged to the G9P23 genotype, and whole-genome sequencing of PoRVA SX2024 confirmed strong homology with reported strains and defined its genotype constellation as G9-P23-I5-R1-C1-M1-A8-N1-T1-E1-H1, highlighting intragenotypic diversity. The TGEV JX2024 isolate clustered within the Purdue subgroup with limited variation. Collectively, these findings delineate the evolutionary landscape of porcine enteric viruses in China and provide valuable reference strains for vaccine development and the optimization of control strategies.